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DMX512A Receive object posted — Parallax Forums

DMX512A Receive object posted

Timothy D. SwieterTimothy D. Swieter Posts: 1,613
edited 2007-12-21 23:51 in Propeller 1
I uploaded my latest DMX Rx Driver to the object exchange. This is the first time posting the object there and will be the place·where I post code and update the object for each new revision.· http://obex.parallax.com/objects/233/·
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The object is version 1.3 and is updated from the past object found on the forum.· Anyone using the past object I recommend to use the new object.· Beware, I changed the name of one of the·public methods to make more sense, at least to me.·
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Thanks to the feedback from the forum on the past object.· I finally got around to doing a little updating of the code and I add more comments and references.· The object now checks for short packet, which are packets that aren't 513·bytes long.· This is the same receive object recently used in my LED bookcase demo.·
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If you have any questions or comments please let me know.
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Enjoy!

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Timothy D. Swieter
tdswieter.com
One little spark of imagination is all it takes for an idea to explode

Comments

  • Timothy D. SwieterTimothy D. Swieter Posts: 1,613
    edited 2007-12-21 03:25
    I updated the object in the object exchange last night. It is now v1.4.

    I updated some of the code comments based on feedback I heard and added a clarification note about wiring a DMX reciever/transmitter. Thanks DynamoBen! I also added the ability to retrieve statistics about the DMX packet such as break time length, MAB length, packet length and break to break length. I was only able to test the stats with the Enttec OpenDMX device I have. If someone else has other devices, please test and let me know how it works. When I added the stats I worked through some math and did some testing to see that the base DMX code still works correctly. I believe that it does, but my transmitter device is sort of lose in its timing so again if you have a problem please let me know.

    Enjoy!

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    Timothy D. Swieter
    tdswieter.com
    One little spark of imagination is all it takes for an idea to explode
  • Chicago MikeChicago Mike Posts: 88
    edited 2007-12-21 17:38
    Really great job on this. I'm hoping I'll have a chance to try this in January when I get back to the states with some consoles I have accurate metrics on. I'll test the break time length, MAB length, packet length and break to break length at different DMX speeds. Again, really, really great!
  • DynamoBenDynamoBen Posts: 366
    edited 2007-12-21 17:56
    BTW I generally use a 75176 in my DMX designs. You would however need to supply a 75176 with 5V.
  • Timothy D. SwieterTimothy D. Swieter Posts: 1,613
    edited 2007-12-21 23:05
    Thanks guys. I remember reading a post by Doug Fleenor about the use of the 75176 chip. It sounds like a robust chip. Two products my company sells both use the Maxim chip which also needs 5 volts.

    Chicago Mike - I would love to hear your results of the testing. Like I said, it may have some problems because I only tested it with my equipment. Let me know what you find out and I will be happy to improve the routine if it is needed.

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    Timothy D. Swieter
    tdswieter.com
    One little spark of imagination is all it takes for an idea to explode
  • DynamoBenDynamoBen Posts: 366
    edited 2007-12-21 23:51
    Normally you would pair the 75176 with a 6N137 for protection. The chip you use has both items in one IC. The reason you might want them separate is they are inexpensive and each can be individually replaced if damaged.
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